<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>网页布局</title>
</head>
<body>

<div id="header" style="border: 1px solid red; width: 100%; height: 100px;"></div>
<img style="margin: 20px; " src="https://www.runoob.com/wp-content/themes/runoob/assets/img/runoob-logo.png" alt="">
<div style="border: 1px solid red;">一级菜单 </div>

</body>
</html>